ENH: Add maintenance script to visualize test times.

Change-Id: I3052bb35555044da6d9833eb0a2fcc0bc2e984ee
ENH: Add a RUNS_LONG label to long running tests.

The tests that can be excluded when their time overhead is burdensome with

  ctest -LE RUNS_LONG

or

  set(CTEST_TEST_ARGS EXCLUDE_LABEL RUNS_LONG)

The labeled tests are less than 1% of the tests but take half of the test
time.

Tests that require a large ITK_COMPUTER_MEMORY_SIZE are also given the
RUNS_LONG label.

Change-Id: I177318caf29a55dc6282b12831d0351d810fbf5c
Merge topic 'test-times'

e3f48b4 ENH: Add a RUNS_LONG label to long running tests.
5ec6c13 ENH: Add maintenance script to visualize test times.